Method of coal and tar distillation



s. P. MILLER 1,942,375

METHOD OF COAL AND TAR DISTILLATION Filed Deo. 1l, 1929 2 Sheets-Sheet lJan. 2, 1934.

ATTORNEYS Jan. 2, 1934. 5 P MULLER- 1,942,375

METHOD OF COAL AND TAR DISTILLATION INVENTOR ATTORNEYS Patented an. 2,1.9344

UNITED STATES METHOD F COAL AN) TAR DISTILLATION Stuart Parmelee Miller,Englewood, N. J., as-

signor to The Barrett Company, New York, N. Y., a corporation of NewJersey Application December 11,1929 Serial'No. 413,253

3 claims. (o1. 20H) This invention relates to thedistillation of the tarproduced at a coke oven plant with production of' pitch and distillateoils, with subsequent coking oi' the pitch thus produced in one or more5 .oi the coke ovens of a coke oven battery.

The process ofl this invention can be carried out at ordinary coke ovenplants such as a Semet- Solvay coke oven plant or a Koppers coke ovenplant, with no alteration to the plant or but slight alterations, 'andwith the addition of a small amount of equipment. The tar recovered fromthe coke oven gases is distilled to pitch according to this invention,and the pitch produced is coked in one or more of th ovens of a cokeoven battery. In this way,v the tar produced at the plant may be readilydisposed of and the quantity of coke produced from a given amount ofcoal will be increased. The coke oven plant may be so operated that theonly major products produced are coke, distillate oils, valuable fuelgases,

ammonia and light oils. 'Ihe disposal of tar at a coke oven plant hasbeen handled in various ways in the past. Often tar has been burned asfuel, but this is undesirable in that tar contains valuableconstituents, such as creosote oil, tar acids, etc.l 'Ihe tar can bedistilled, but tar distillation lplants are not ordinarily associatedwith coke oven plants, and although methods ot coking pitch-are known,hitherto no method has been suggested for coking pitch in one or more ofthe ovens ot a coke oven battery with the saving in cost of equipmentand operation which would result. By distilling tar at or near the cokeoven plant, especially by distilling the tar by direct contact with thehot gases from `selected ovens of the plant, and coking the pitchproduced in one or more of the ovens of a-battery, a high yield of oilsmay be obtained and added coke produced at the coke oven plant.

According to this invention, the tar recovered from the coke oven gasesis distilled to pitch and the pitch is charged to one or more of theovens oi' the coke oven plant. The ovens to which the pitch is chargedare heated by the same equipment employed for heating the balance oi'the ovens oi the battery in which coal is coked. The vapors from theoven or ovens in which pitch is coked may be condensed in the condensingsystem provided for the treatment oi the gases coming from the cokeovens in which coal is coked, or if desired, special condensing meansmay be employed. The pusher provided i'orv removing the coke from thecoke ovens may bel used for pushing the coke resulting from the cokingof the 66 pitch, and the Acoke 'car and quenching system tarry oils fromthe condensers may be distilled invention, where the pitch produced isto be conemployed for treating the coke from the ovens charged with coalmaybe employed for handling and quenching the coke resulting from thecoking of the pitch. When pitch is coked at a coke oven plant, there isconsiderable economy in thus no utilizing equipment provided for thehandling of the coke produced from coal in the balance of the ovens, andat the same time producing a high grade of metallurgical pitch coke oflow ash and sulfur content and high B. t. u. value.

According to this invention, coke oven gases may be treated in the usualway for the removal oi tar. Any suitable means for cooling the gases maybe employed. Either the heavy vtar which, separates from coke oven gaseson cooling in the 7- collector main or the lighter tar which separatesfrom the gases in the condensers may alone be distilled to pitch and thepitch thus obtained convetted to coke, or total tar comprising bothheavy tar from the collector main' and lighter tar or u to pitch andthe-pitch converted to coke, according to this invention.

A coke oven battery of, i'or example, 60 ovens, may be operated as aunit or where a number of so batteries are located at the same coke ovenplant, the pitch resulting from the distillation of all of the tar tromthe various batteries may be distilled in a number 'of the ovens o!onevbattery.

The tar may be distilled to pitch by any suitable method. The'tar may bedistilled to pitch in al pipe coil still and vacuum distillationmay beemployed toadvantage to produce a high melting point pitch. Steamdistillation may be used to distill the tar to pitch. -It isadvantageous to produce a high melting point pitch so that roaming ofthe pitchin. the oven is eliminated or reduced to a minimum.

According to a preferred method of distillation in whichpitch of highmelting point is'produced and a high yield ot oils-is obtained, tar inthe form o! a line intense spray is sprayed into hot` coke oven gases.Such a method oi producing pitch of high melting point is particularlysuited for use in connection with the process 'of this 10 verted to cokeat the coke oven plant. The hot coke oven gases from several of theovensare separately collected and passed through a stillyandthetarisdistilledbybeingsprsyedintothese hot gases. In such a still,using thegases from -iour to six ovens, it is possible ,to ordinary cokeoven tar at a rato sumcientito produce the amount oi-pitch which can bedistilled in an ordinary coke oven. It the pitch is coked in n0 an ovenon an operating cycle of about to 22 hours, one still, utilizing theheat of four to six ovens, can produce `siiiillcient high melting pointpitch to maintain one oven in continuous operation. Such a system canoperate on a basis of converting about four million gallons of tar peryear to pitch and then coke. It is to be understood that because thequality and the quantity of the tar produced at different plants, andeven at the same plant under different operating conditions, varies, andbecause-they amount of heat contained in the gases from asingle ovenvaries, depending upon the quality of coal employed, the length ofthecoking cycle, etc., therefore. gures such as the above given inconnection with such a system, can be only approximations.

into a coke` oven in liquid form, to be converted to coke, or it maybechilled and solidified before being charged to the oven. When charged tothe oven in liquid form, the pitch may be charged in a continuous streamand pitch already charged to the oven will be coked whilefresh pitch isbeing added to the oven. As the pitch in the oven is distilled andcoked, more pitch is added to the oven and the coke formed inthe ovenbuilds up until the entire mass of pitch is coked. In such a cokingoperation, the temperature, quantity and amount of gases leaving theoven is more or less uniform throughout the greater portion of thecoking operation. 1

Instead of charging the pitch to the oven continuously, the oven may becharged intermittently. The pitch may be charged to the oven in fourportions, for example, by admitting a fourth of the total charge ofpitch to the oven at each charging operation, and converting the pitchin the oven after each charging operation to coke or semi-coke beforecharging more pitch into the oven. When the coking is carried on in thismanner, the temperature, amount and composition of the vapors comingfrom the oven in which the pitch is coked, will vary. Where severalovens are vemployed for the coking of pitch,

. the ovens may be charged intermittently lin this manner but the chargemay be so regulated that by combining the vapors from the several ovensa vapor stream of substantially uniform tempera-- ture,l composition andamount may be obtained.

'I'he vapors coming from the oven inwhich the pitch is coked may betreated in any one of several ways according to this inventio They maybe collected and cooled in a condensing system entirely separate fromthe condensing sysc tem employed for vcooling the coal distillationgases, or they lmay be collected and cooled in admixture with the coaldistillation gases.

The hot gases and vapors from the ovens in which the pitch is coked maybe employed for the distillation of tar by bringing the tar into directcontact with them. Methods of distilling pitch in which a gas and vaporstream of substantially uniform temperature and composition ismaintained for a prolonged period of time, adapt themselves to suchdistillation of tar more readily than a system in which the amount andtemperature, etc. of the gases varies considerabl over a short period oftime.

provided for collecting the coal distillation gases and vapors fromthose ovens in which coal is coked', and the combined gases and vaporsare partially cooled in the collector main and further cooled in thecondensers provided for the treatment of the coal distillation gases.The tar which separates from the gases on cooling is a combined tar andon distilling this tar to pitch of high melting point, an outlet for allof the tar produced at the plant is provided, and the pitch thusobtained may be coked so that the only products of such an operationvarecoke, clean oils and gases.

The tar formed by cooling the vapors from the coking of pitch differsfrom ordinary coke oven tar. It contains less lower boiling constituentsthan ordinary c ke oven tar and contains a relatively large am unt ofhigh boiling constituents including greasy and resinous compounds whichnection with the accompanying drawings and more particularly with theoperation of a Semet- Solvay coke oven battery with distillation of tarby direct contact with the hot coke oven gases from several of the ovensof the battery, but it is intended and is to be understood that the invention is not limited thereto.

In the drawings:

l isa plan view of a coke oven battery equipped for carrying out thisinvention;

Fig. 2 is an elevation showing the tar still with a pitch feed to thetwo ovens at the end of the coke oven block; and

Fig. 3 is a section on the line 3-3 of Fig. 2.

The ovens of the coke oven battery V5 connect in the `usual way with thecollector main 6 through uptake pipes 7. The ovens are heated in theusual manner as by heating nues within the separating walls. In thedrawings the ovens are shown as being provided with horizontal heatingdues 'I'. Means is provided for spraying the gases in the uptake pipesand in the collector main with ammonia liquor from the line 8. The v arecollected in the storage tanks 12v and ammonia liquor is separatelycollected in ammonia liquor storage tanks. An exhauster 13 is providedfor drawing the gases through the system.

The two ovens 15 and 16 located at the end of the'coke oven batteryadjacent to the pinion wall 11 are `connected through the usual uptakepipes 'l with the collector main 6. Tar from the gases coming oiI fromthe ovens 15 and 16 is distilledwith tar from the coal distillationgases coming from the other ovens. The tar and ammonia liquor are drawnoil of the collector main at the end of the ovenadjacent to the pinionwall to the decanter 18. The heavy tar and ammonia liquor are separatelydrawn oilin th storage tanks 19 and 20. f

, Either the tarry oil from the tanks 12 or the heavier tar from thetanks 19, or a blend of both of thesetars may be distilled awarding tothis invention and tar from the two end coke ovens and 16 may be blendedwith this tar for distilla tion in the still described below. Any tarproducedl in connection with the operation of a gas producer or watergas set employed .for making gas for heating the ovens, may be added tothis tar to be distilled in the still where desirable. l,

The tar still is indicated at 25. It connects through the' hot gasheader 26 with uptake pipes '27 on a number of the ovens, preferablythose adjoining the ovens 15 and 16 in which pitch is coked. By a propermanipulation of valves in the uptake pipes 27 and the uptake pipes 7 onthese same ovens, the hot gases from these ovens may be diverted eitherto thecollector main 6 or through the'hot gas header 26 into the still25.

Inthestillisaroll28. Itisadaptedtobe driven at a high speed, forexample, 900 to 1200 R. P.. M. by the motor 29. Rapid rotation of thisroll throws a fine intense spray of tar into the hot gases, therebyexposing a large surface of the tar to the distilling eiiect of the hotgases whereby distillation is rapidly and eiilciently eifected withoutany considerable decomposition of the tar. The fine intense spray of tarsimultaneously scrubs the gases, removing entrained impurities present'in the gases. Ihe hot gases leave the still enriched in oil vapors andsubstantially free from entrained impurities.l 'lhey leave the stillthrough the tower 25'. The tar to be distilled is supplied to this towerthrough the line 30. Baming means 31 and 32 are provided in the tower toremove entrained particles of tar spray from the gases. The tar lsprayedinto the gases Dessins' up through the tower 25' is partially distilledand the semi-pitch produced is supplied through the line 33 to the endof the tar stili at which the hot gases enter. In the still 25, thesemi-pitch is distilled to pitch of high melting point. This pitch isdrawn ci! -from the still through the coke trap 34 and the leveling `arm35. The leveling arm 35 has been shown as an open-ended pipe throughvwhich the pitch flows into the pitch tank 44. The pitch isadvantageously distilled to a high melting point, for example, 400 F. orhigher.

The'hot gases and vapors from the tower 25' pass through the main 36 toa heat interchanger 37 in which they, are brought into indirect heatinterchange relation with the tar to be distilled. The tar is thuspreheated and heat economy -is effected. Heavy oils are separated fromthe gases and these are collected in-the storage tank 38. The gases thenpass to a further condenser which may be a direct condenser 39 in whichthe gases are sprayed with water or ammonia liquor from the line 40.This condenser drains into the decanter 41 and separate means areprovided at 42 and 43 for collecting the ammonia liquor and lighteroils.

'Ihe high melting point pitch may be supplied directly from the still tothe ovens, or it may be rst cooled and soliditled and supplied to theovens in solid form or, according to thepreferred Although two ovens 15and 16 are shown equipped for coking pitch, but one oven may be employedat one time and the other oven may be held in reserve so that when it isnecessary to shut one of the ovens down for repairs or for otherreasons, the other oven may be employed for the coking of pitch. In themeantime, it may be employed for the distillation of coal. EachY of therovens 15 and 16 is provided with a' pitch feed 45 which is connectedwith the pitch storage tank 44 by the heavily insulated line 46.Suitable valve means indicatedat 47 is provided for controlling the iiowof pitch through this line, and

means for blowing the line with steam after use is advantageouslyprovided. Ihe pitch feeds are removably mounted when they enter the oven.through an oven door as shown; When pitch is to be added to the ovensin a continuous manner with continuous coking of the pitch andcontinuous production of coke, each oven is advantageously provided withseveral pitch feeds which may be llocated in the top of the oven or atany suitable point in the oven.

The arrangement here shown is particularly adapted for an operation in'which va quarter of 100 the total charge of pitch is charged to the ovenat each charging operation, and there are four charging operationsduring each coking cycle. The pitch is charged intermittently, andbefore any additional pitch is added, the pitch already present in theoven is converted to coke or semicoke. l

After the full charge has been added'to the ovens and the cokingoperation is completed, the charge of coke in the ovens is removed inany suitable manner. The pusher which operates on tracks (not shown)under the cross-over main and which is employed for pushing the cokeresulting from the distillation of co'al in the balance of the ovens ofthe battery, may be employed for pushing the coke from these ovens 15and 16. The coke car. which operates on tracks atthe opposite side ofthe battery may be-employed for receiving the coke as it is pushed fromthe ovens 15 and 16. The coke quenching equip- 120 ment-employed forcooling the coke produced from the coal may be employed for cooling thepitch coke. In this way the cost of the original equipment is ikept at aminimum /by employing the same means for handling the coke produced fromcoal and the coke produced from pitch. The tar-distilling means shownyields a high percentage of distillate, -and pitch of high melti ingpoint is produced. By the combined equipment here shown, a high yield ofdistillate is ob- 133- tained and the battery may be so operated thatthe only maior products of the operation are coke, distillate oils, andgas and light oil.

I claim: v l

1. The method of operatingv a coke-oven bat- 135 tery involving a seriesof coking chambers separated by heating walls, which comprises cokingcoal in one portion of said ovens and coking pitch in a second portionthereof, withdrawing hot gases resulting. from the coking of coal and14,1 cooling them to separate tar, passing the tar in heat yexchangeVrelation with the hot gases from a portion of the ovens of the batterywhereby said tar is distilled to pitch, and introducing said pitch intosaid second portion of the ovens of the battery and coking it therein.

2. The method of operating a coke-oven battery -which comprises cokingcoal in a portion of the ovens of the battery to form a coke from coal,coking pitch in another portion of the ovens -to separately formpitch-coke, withdrawing thel vhot gases resulting from the coking of thecoal coking pitch in another portion thereof, withdrawing hot gasesresulting from the coking of the coal and hot gases resulting from thecoking of the pitch,combining these gases and cooling them to separatetar. intensely spraying into the hot gases from a minor portion of theovens of the battery the tar thus separated whereby said tar isdistilled to pitch and whereby entrained tar particles are scrubbed fromsaid gases, cooling the gases to condense clean oils, and introducingsaid pitch into said other portion of the ovens of the battery andcoking it therein.l

S. P. MILLER.

